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Robert Downing

Publications and source records attributed to Robert Downing.

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Revisiting Stellar Systems J0946 and V723 Monocerotis: A Study of Mass Gap Black Hole Candidates

In 2023, Rowan et al. reported the discovery of a black hole (BH) companion to J0946, following the misidentification of V723 Mon by Jayasinghe et al. as containing a "mass-gap" BH. This article reproduced Rowan and Jayasinghe's results on these systems by estimating stellar parameters via Markov Chain Monte Carlo solvers. We implemented Bayesian statistical modeling through the software ExoFit and PHysics of Eclipsing Binaries (PHOEBE). For J0946, we found a higher inclination of i = 72 degrees and a companion mass of 2.78 solar masses, lower than what Rowan estimated. V723 Mon's results aligned with recent estimates by El Badry et al., yielding an inclination of i = 74 degrees and a mass of 2.56 solar masses. We tested this method on stars from Gaia DR2 and the NASA Exoplanet Archive, agreeing with previous findings that these datasets do not exhibit strong indications of stellar-mass black hole systems.

astro-ph.SR

Track Extrapolation and Distribution for the CDF-II Trigger System

The CDF-II experiment is a multipurpose detector designed to study a wide range of processes observed in the high energy proton-antiproton collisions produced by the Fermilab Tevatron. With event rates greater than 1MHz, the CDF-II trigger system is crucial for selecting interesting events for subsequent analysis. This document provides an overview of the Track Extrapolation System (XTRP), a component of the CDF-II trigger system. The XTRP is a fully digital system that is utilized in the track-based selection of high momentum lepton and heavy flavor signatures. The design of the XTRP system includes five different custom boards utilizing discrete and FPGA technology residing in a single VME crate. We describe the design, construction, commissioning and operation of this system.

physics.ins-det